Crows as janitors?

That's what a theme park in France is trying to do, at least with regards to cigarette butts and bits of trash. The park has trained six crows to pick up this type of trash and put it in a box. When the crow does so, he is rewarded with some food.

This is not the first time this has been tried.

It reached the level of a TED Talk in 2008. The gig was a crow vending machine that let birds trade coins for peanuts. The concept, though, did not fly. Then, last year “The Crowbar” was developed; it would teach crows to pick up half-smoked cigarettes. It was greeted with muted interest.

Ornithologists and bird experts are skeptical that wild birds can be trained to pick up after humans. Birds raised in captivity, though, have a better chance.